Showing papers by "Stephen Shennan published in 2010"

The cophylogeny of populations and cultures: reconstructing the evolution of Iranian tribal craft traditions using trees and jungles

Abstract: Phylogenetic approaches to culture have shed new light on the role played by population dispersals in the spread and diversification of cultural traditions. However, the fact that cultural inheritance is based on separate mechanisms from genetic inheritance means that socially transmitted traditions have the potential to diverge from population histories. Here, we suggest that associations between these two systems can be reconstructed using techniques developed to study cospeciation between hosts and parasites and related problems in biology. Relationships among the latter are patterned by four main processes: co-divergence, intra-host speciation (duplication), intra-host extinction (sorting) and horizontal transfers. We show that patterns of cultural inheritance are structured by analogous processes, and then demonstrate the applicability of the host–parasite model to culture using empirical data on Iranian tribal populations.

Comparative Anthropology and Human Inequality

Abstract: This is an outstanding set of papers that reasserts the importance of one of anthropology’s long-standing goals—the comparative evolutionary study of societies. The issue that it addresses, the factors affecting the emergence of economic inequality, could not be more significant. Making comparisons involves collecting comparable data from different societies, and the systematic collection of consistent comparative quantitative information that provides the basis for these papers represents a major achievement of lasting value. Asking new questions almost always involves the collection of inform ation that earlier scholars had not deemed important, but it is still difficult not to be disappointed that after 100 years of anthropological fieldwork, the number of cases from which the authors have been able to extract the data they need is very limited. A particular conceptual advance the authors make, central to their comparative approach, is their characterization of what might at first seem very disparate phenomena—acquisition of skills, numbers of exchange partners, and sizes of cattle herds, for example—as different forms of wealth (embodied, relational, and material), making use of the ideas of human capital and parental investment from economics and behavioral ecology. They also cleverly get around the issue of the multiple institutions and practices through which intergenerational resource transfers are affected by measuring outcomes, the degree to which parent and child values are correlated. This theoretically justified creative abstraction in defining appropriate variables is matched by the extremely powerful and sophisticated analytical methods used to obtain the many interesting results that provide the basis for the papers’ conclusions. Not least of these results is their demonstration of the inherited inequalities that exist in apparently egalitarian hunter-gatherer societies and that have a major impact on individuals’ life chances through the generations. Indeed, one conclusion that could be drawn from these results is that the claimed egalitarianism of many if not most huntergatherer societies is less a result of an evolved human psychology of “reverse dominance” (Boehm 1993) and more one of ecological conditions relating to the nature of resources. The idea that the key to the development of major inequalities in human societies might be the nature of what counts as wealth and the extent to which it is transmitted— and, specifically, the emergence of material wealth and its inheritance—is not new in itself. It is there in the property rights discussions of the “new institutional economics” and in Bowles’s (2004, chap. 11) earlier work, as well as in the discussions of Rogers (1995) and in Hayden’s (1997; Hayden, Bakewell, and Gargett 1996; see also Shennan 2002, chap. 8) studies, as the authors note. Moreover, the foundation of the explanation advanced here for the importance of material resources, especially land but also animals—that when they are in short supply, their predictability and excludability give lasting, reliable benefits that justify paying the costs of investing in improvements and of defending them and excluding others—goes back some time, not least to the early work of author Eric Smith (Dyson-Hudson and Smith 1978). What is new is the systematic demonstration of the high rates of transmission of material wealth and the higher levels of inequality associated with it compared with other wealth forms. It follows from this quite naturally, as the authors indicate, that the key to the growth of inequality in the Holocene is the greatly increased potential offered by certain forms of agriculture for more or less unlimited inequality arising from the inheritance of material resources, because of the great potential that they create for the rich to get richer over the generations, in comparison with the more limited and less reliable possibilities offered by embodied and relational wealth. On this basis, their attack on the often-made claim that the key to the inequality generated by agriculture is the possibility of surplus generation is entirely convincing; rather, surplus generation is a by-product of the differential accu-